1. Field of the Invention
The present invention relates to a disk cartridge, and more particularly, to a disk cartridge which stores a disk and protects a recording surface of the disk from contamination sources including dust and fingerprints.
2. Description of the Related Art
Generally, a disk cartridge stores a disk, which is an information recording/reproducing medium, and is mounted in a disk drive apparatus. FIG. 1 shows a conventional disk cartridge 100 comprising a case 101 which stores a disk D, a shutter 110 which is installed and rotated in the case 101 to selectively open or close an aperture 102 on the case 101, so as to allow a pickup (not shown) of a disk drive apparatus (not shown) to access the disk D, and a cover 103 which is fixed on an upper portion of the case 101.
An opening 103b is formed on the cover 103 to replace the disk D, and separation prevention levers 103a are installed and slide on the cover 103 to prevent the disk D from being separated through the opening 103b. To mount the disk D, the separation prevention levers 103a move backward so as not to interfere with the disk D. After the disk D has been mounted, the separation prevention levers 103a move forward, as shown in FIG. 1, so that respective front ends of the separation prevention levers 103a prevent the disk D from being separated through the opening 103b. 
FIGS. 2A and 2B show plan views of the disk cartridge 100 of FIG. 1 where the disk cartridge 100 having the disk D is introduced into the disk drive apparatus. In response, an opening lever 130 of the disk drive apparatus pushes a locking piece 111a to release a protrusion 11c of the shutter 110 from a groove 101a of the case 101. Sequentially, the opening lever 120 pushes an interference piece 111b to rotate the shutter 110 as shown in FIG. 2B. In this case, the shutter 110 is formed of first and second shutter units 111 and 112, which are installed and rotated on rotation shafts 110a, and engage each other by an interlock saw tooth portion 113. Therefore, where the first shutter unit 111 integrally connected to the interference piece 111b rotates in, for example, a clockwise direction, the second shutter unit 112 rotates in a counterclockwise direction so as to have the first and second shutter units 111 and 112 open the aperture 102. Thus, the pickup of the disk drive apparatus can access a recording surface of the disk D through the aperture 102 to record/reproduce information. Although not shown in the drawings, a torsion spring is installed on the rotation shaft 110a, between the first shutter unit 111 and a surface of the case 101 to elastically bias the first shutter unit 111 in a counterclockwise direction, i.e., in a direction to close the aperture 102. Consequently, where a force applied to the opening lever 120 is removed, the shutter 110 returns to a closed state.
In such a structure, a force applied to the shutter 110 through the aperture 102 easily deforms the shutter 110 where the shutter 110 is closed. In other words, since only one end of the shutter 110 is coupled to the rotation shafts 110a, while a user pushes the other side of the shutter 110 through the aperture 102, the shutter 110 may be deformed. Accordingly, the shutter 110 is not smoothly opened or closed and a gap may occur between the first and second shutter units 111 and 112. Therefore, the shutter 110 cannot properly perform as a shutter to open and close the aperture 102 of the case 101.
Additionally, since the shutter 110 is installed in the case 101 so as to mount the disk D on the shutter 110, the recording surface of the disk D, i.e., a lower surface of the disk D in the drawings, may contact the shutter 110 during an opening and closing of the shutter 110. Thus, scratches may occur on the recording surface of the disk D.
Therefore, a structure of a disk cartridge which prevents deformation of a shutter and protects a recording surface of a disk during opening and closing operations of the shutter is required.